The zoogeography of trematodes of marine fishes

Abstract

Examples are cited of the zoogeographical significance of the parasites of Lota lota, Aplodinotus grunniens, Coregonus, Cyprinidae, Anguilla spp., and Galaxias. Of 20 species of trematodes of Atlantic eels ( Anguilla) 14 are shared with marine fishes, 5 with freshwater fishes, and only one species is limited to the eel. Pacific eels are known to have 3 genera and 8 species of trematodes peculiar to them. A Pacific origin of Anguilla is suggested. Helminths of Galaxias, freshwater fishes of South America, New Zealand, and Australia, include 4 species of trematode and 1 acanthocephalan. All the trematodes have marine Pacific affinities and support the idea that Galaxias may once have been a marine Pacific genus. One of the trematodes and the acanthocephalan are related to species from antherinid fishes of Argentina, but both belong to genera having wide marine distribution and in the case of the acanthocephalan wide fresh-water distribution as well. Knowledge of the zoogeography of Monogenea is scanty. Only the Gyrodactyloidea are given brief consideration. A general review, particularly at the species level, is given of the zoogeography of digenetic trematodes of marine fishes of various regions where they are moderately to well known, namely: European North Atlantic; Mediterranean; Red Sea; Woods Hole, Massachusetts; Tortugas, Florida; New Zealand; Japan; Indian coasts. In general, the distribution pattern is in agreement with that known for other phyla. A large percentage of the trematodes of each region is peculiar to it; that is, not widely distributed. Strong similarity of trematodes is pointed out between: 1. (1) European Atlantic and the Mediterranean 2. (2) Tortugas, Florida (shallow water) and Bermuda 3. (3) Tortugas, Florida (shallow water) and tropical American Pacific Considerable similarity occurs between: 1. (1) Deeper water Tortugas and distant cold seas 2. (2) New Zealand and the North Atlantic and North Pacific There are five hemiurid genera, involving a total of 31 species, common in cold seas of both hemispheres and elsewhere represented only in fishes of rather deep water. 3. (3) Red Sea and the warm Pacific 4. (4) Celebes and Japan Strong dissimilarity occurs between: 1. (1) Deepwater and shallow water at Tortugas 2. (2) Shallow water Tortugas and North Atlantic 3. (3) Mediterranean and the Red Sea